In many applications, it is useful to detect changes in magnetic field to track translational motion, rotational motion, proximity, speed and the like. GMR (Giant Magnetoresistance), AMR (Anisotropic Magnetoresistance), TMR (Magneto Tunnel Effect), and CMR (Colossal Magnetoresistance) sensors, as well as Hall-effect sensors, are different types of magnetoresistive sensors that can measure changes in magnetic field.
Typically, a magnetoresistive sensor has a high sensitivity in a so-called “working range” of the sensor. In this context, “high sensitivity” means that a small change in magnetic field applied to the sensor leads to a large change in resistance as measured by the sensor. Outside of the working range, unfavorable behavior of the magnetoresistive effect, such as saturation for example, limits the use of the sensor for many applications. Although existing magnetoresistive sensor systems are adequate in many respects, existing sensor systems suffer from a limitation in they have been unable to maximize the sensitivity and/or working range of the sensors.